This invention relates to an aquarium filter assembly including a water holding tank with filter material and an internal pump for driving water through the filter material. More particularly, the invention relates to an aquarium filter assembly having a plurality of water-holding tanks symmetrically disposed about the pump, and wherein the pump is provided with a housing configured with water ports and a flow diverter for directing water uniformly to all tanks, an impeller of the pump and the impeller housing having being configured for reduced noise.
An aquarium is constructed generally as a tank for holding water and marine life, and includes a filtration system for filtering the water. One form of external filtration system of particular interest herein is constructed as a filter assembly which includes a filter tank with filtration material therein, and a pump for driving water through the filtration material. The assembly is provided with an inlet water conduit for induction of water from the aquarium tank and a spillway for returning water from the filter assembly to the aquarium tank. The pump, which includes an electric motor and an impeller driven by the motor, may be located in a bottom portion of the assembly with the impeller directed upward for engaging with the inlet water conduit for directing water into the filter tank. The filter assembly is constructed preferably in a fashion wherein the filter assembly is draped exteriorly over a wall of the aquarium tank with the filter tank and pump located outside the aquarium tank. The inlet conduit and the spillway arch over the wall of the aquarium tank to communicate with water in the aquarium tank. The foregoing configuration of a filter assembly has proven to be very convenient in use, and very effective in operation. Such filter assemblies and the construction of various parts thereof are covered in one or more of the following issued patents, all issued to the assignee of the present invention: U.S. Pat. Nos. 4,512,885; 4,602,996; 4,735,715; 4,761,227; 4,783,258; 4,842,727 and 4,861,468.
There has also been provided a filter assembly in a larger size for use with a larger aquarium. In the larger size of filter assembly, a plurality of filtration elements are employed in separate filter tanks with water flowing along parallel courses to the respective filter tanks. Separate outlet spillways are provided for separate ones of the filter tanks to facilitate the flow of water, and also to provide a convenient configuration to the filter assembly for draping the filter assembly over the wall of the aquarium tank. A single pump impeller is employed in a common inlet conduit.
In one configuration of the larger proposed filter assembly, there are two filter tanks located side-by-side, both tanks contacting a wall of the aquarium tank upon a mounting of the filter assembly upon the wall of the aquarium tank. In order to distribute water uniformly to both filter tanks, and in order to provide a structure which is rigid and convenient to use, a common inlet conduit is located in a central transverse plane of the assembly between the two filter tanks. In prior art assemblies, the motor unit includes a collar which extends into the inlet chamber and forms a housing which envelops the impeller, and is provided with outlet ports. Upon rotation of the impeller about a longitudinal axis thereof, the impeller causes a stream of inlet water to flow in the housing and which exits the housing via the outlet ports in a direction generally perpendicular to the rotational axis to flow toward the two filter tanks. The two filter tanks are formed as portions of a larger housing including a central corridor for directing water from the impeller to the two filter tanks.
The foregoing filter assembly with the two filter tanks has proven to be effective in the filtration of the aquarium water. However, two problems have been noted. First, due to the rotational movement of the impeller, outlet water from the impeller tends to be directed preferentially to one of the two filter tanks. This results in a utilization of a filter element in one tank at a higher rate than the filter element in the other tank with the result that filter replacement is required at more frequent intervals than would be the case if both filter elements were utilized at the same rate. Secondly, the use of the rotating impeller to provide the stream of water at a substantially higher rate of flow, due to the need to provide water to a plurality of filter tanks rather than a single filter tank, produces a sufficient amount of noise to be objectionable to persons observing marine life in the aquarium. Furthermore, during operation a stream of water is formed in the inlet chamber which rises toward the cover of the filter and can cause vibration in the cover on the filter.